Applications of satellite technology to broadband ISDN networks

Two satellite architectures for delivering broadband integrated services digital network (B-ISDN) service are evaluated. The first is assumed integral to an existing terrestrial network, and provides complementary services such as interconnects to remote nodes as well as high-rate multicast and broadcast service. The interconnects are at a 155 Mbs rate and are shown as being met with a nonregenerative multibeam satellite having 10-1.5 degree spots. The second satellite architecture focuses on providing private B-ISDN networks as well as acting as a gateway to the public network. This is conceived as being provided by a regenerative multibeam satellite with on-board ATM (asynchronous transfer mode) processing payload. With up to 800 Mbs offered, higher satellite EIRP is required. This is accomplished with 12-0.4 degree hopping beams, covering a total of 110 dwell positions. It is estimated the space segment capital cost for architecture one would be about $190M whereas the second architecture would be about$250M. The net user cost is given for a variety of scenarios, but the cost for 155 Mbs services is shown to be about $15-22/minute for 25 percent system utilization

Digital document imaging systems: An overview and guide

This is an aid to NASA managers in planning the selection of a Digital Document Imaging System (DDIS) as a possible solution for document information processing and storage. Intended to serve as a manager's guide, this document contains basic information on digital imaging systems, technology, equipment standards, issues of interoperability and interconnectivity, and issues related to selecting appropriate imaging equipment based upon well defined needs

Cognitive Information Processing

Contains research objectives and summary of research on fourteen research projects and reports on four research projects.Joint Services Electronics Program (Contract DAAB07-75-C-1346)National Science Foundation (Grant EPP74-12653)National Science Foundation (Grant ENG74-24344)National Institutes of Health (Grant 2 PO1 GM19428-04)Swiss National Funds for Scientific ResearchM.I.T. Health Sciences Fund (Grant 76-11)National Institutes of Health (Grant F03 GM58698)National Institutes of Health (Biomedical Sciences Support Grant)Associated Press (Grant

Digital encoding of black and white facsimile signals

As the costs of digital signal processing and memory hardware are decreasing each year compared to those of transmission, it is increasingly economical to apply sophisticated source encoding techniques to reduce the transmission time for facsimile documents. With this intent, information lossy encoding schemes have been investigated in which the encoder is divided into two stages. Firstly, preprocessing, which removes redundant information from the original documents, and secondly, actual encoding of the preprocessed documents. [Continues.

Issues in multi-media information networks

In an integrated service environment, where users exchange various types of aural and visual information, networks should appear friendly to its users providing tools for management of multi-media information. Networks should also efficiently satisfy diverse performance requirements of different information being exchanged.In this paper we present new architecture for integrated service networks being investigated and developed by the Distributed Computation and Communication Group at the Department of Computer Science in the Columbia University. Research efforts are devoted to developing both (1) document management software to allow users to manipulate and relate text/graphics/voice information in a dynamic way, and (2) a tree network architecture for reliable and efficient exchange of multi-media information

Telecommunications media for the delivery of educational programming

The technical characteristics of various telecommunications media are examined for incorporation into educational networks. FM radio, AM radio, and VHF and UHF television are considered along with computer-aided instruction. The application of iteration networks to library systems, and microform technology are discussed. The basic principles of the communications theory are outlined, and the operation of the PLATO 4 random access system is described

On the proposed integrated services digital network

The ultimate aim of this dissertation is neither to increase the state of the art in networking technology nor to predict the future structure of telecommunications networks. It is an attempt to raise the awareness of both the author and the reader as to the evolutionary forces driving vast changes in the telecommunications field. The impact of these changes will significantly alter the way we live and conduct business in the Information Age. For those involved with the communications field, the ability to make sound business decisions will require an in-depth knowledge of the technology and services that compose ISDN. Therefore this paper will explore the motivating forces, the potential services, and the technical components in the emerging Integrated Services Digital Network (ISDN). My interest in data communications was kindled at RIT and has continued in my work, both as a systems programmer in the telecommunications division at the Travelers Insurance Company and as a printing systems analyst for Xerox Corporation. This thesis has helped me answer both personal and professional questions about the future of telecommunications and to share this information with others

Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression

Deep Space Network information system architecture study

The purpose of this article is to describe an architecture for the Deep Space Network (DSN) information system in the years 2000-2010 and to provide guidelines for its evolution during the 1990s. The study scope is defined to be from the front-end areas at the antennas to the end users (spacecraft teams, principal investigators, archival storage systems, and non-NASA partners). The architectural vision provides guidance for major DSN implementation efforts during the next decade. A strong motivation for the study is an expected dramatic improvement in information-systems technologies, such as the following: computer processing, automation technology (including knowledge-based systems), networking and data transport, software and hardware engineering, and human-interface technology. The proposed Ground Information System has the following major features: unified architecture from the front-end area to the end user; open-systems standards to achieve interoperability; DSN production of level 0 data; delivery of level 0 data from the Deep Space Communications Complex, if desired; dedicated telemetry processors for each receiver; security against unauthorized access and errors; and highly automated monitor and control

COMPUTER MEDIATED COLLABORATIVE DESIGN IN ARCHITECTURE: THE EFFECTS OF COMMUNICATION CHANNELS ON COLLABORATIVE DESIGN COMMUNIATION

Up till now, architects collaborating with other colleagues did so mostly face-to-face (FTF). They had to be in the same space (co-located) at the same time. Communi-cation was ‘spontaneous’ and ideas were represented, whether verbal or non-verbal, by talking and using ‘traditional drawing tools’. If they were geographically displaced, the interaction was then space affected as well as the probability of being time affected. In this case communication was usually mediated through the tele-phone, and graphically represented ideas were sent by Fax or posted documents. Recently, some architectural firms started using modems and Internet connections to exchange information, by transferring CAD drawings as well as design informa-tion, through e-mail and file transfer protocol (FTP). Discussing ideas in architecture, as a more abstract notion, is different from discuss-ing other more concrete arguments using video conferencing. It is more important to ‘see’ what is being discussed at hand than ‘watch’ the other person(s) involved in the discussion. In other words the data being conveyed might be of more impor-tance than the mode of communication. Taking into consideration recent developments in computer and communication technologies this thesis investigates different communication channels utilised in architectural collaboration through Computer Mediated Collaborative Design (CMCD) sessions as opposed to FTF sessions. This thesis investigates the possi-ble effects these different channels have on collaborative design in general and col-laborative design communication in particular. We argue that successful CMCD does not necessarily mean emulating close prox-imity environments. Excluding certain communication channels in a CMCD envi-ronment might affect the flow and quantity of synchronous collaborative communica-tion, but not necessarily the quality and content of mutually communicated and rep-resented design ideas. Therefore different communication channels might affect the type of communication and not necessarily the content of the communication. We propose that audio and video are not essential communication channels in CMCD environments. We posit that architects will collaborate and communicate design representations effectively although with some differences, since those two chan-nels might cause interruptions and successful collaborative sessions can take place without them. For this purpose we conducted twenty-four one-hour experiments involving final year architecture students all working to the same design brief. The experiments were divided into three categories, FTF, full computer mediated collaborative design sessions (CMCD-a; audio-video conferencing plus whiteboard as a shared drawing space) and limited computer mediated collaborative design sessions (CMCD-b; with Lambda MOO used as a chat medium plus whiteboard as a shared drawing space). The experiments were video and audio taped, transcribed and coded into a custom developed coding scheme. The results of the analysed coded data and observations of the videotapes provided evidence that there were noticeable differences between the three categories. There was more design communication and less communication control in the CMCD-b category compared to the FTF and CMCD-a categories. Verbal communi-cation became shorter and straight to the point in CMCD-b as opposed to spontane-ous non-stop chat in the other two categories. Moreover in CMCD-b the subjects were observed to be more reflective as well as choosing and re-examining their words to explain ideas to their partners. At times they were seen scrolling back through the text of the conversation in order to re-analyse or interpret the design ideas at hand. This was impossible in FTF and CMCD-a sessions, since the sub-jects were more spontaneous and audio representations were lost as soon as they were uttered. Also the video channel in the CMCD-a category was ignored and hardly used except for the first few minutes of the experiments, for a brief exchange of light humour on the appearance of each subject. The results obtained from analysing the experiments helped us conclude that differ-ent communication channels produce different collaborative environments. The three categories of communication for architectural collaboration explored in our ex-periments are indicative of the alternatives available to architects now. What is not clear to architects is why they would choose one category over another. We pro-pose that each category has its own strengths and difficulties for architectural col-laboration, and therefore should be selected on the basis of the type of communica-tion considered to be most effective for the stage and tasks of the design project